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Fencer Vulns
medium 6.8

CVE-2021-42553 json

STM32 USB Host Library Buffer Overflow

published 2022-10-21 4 y ago modified 2026-10-08 31 d ago also EUVD-2021-29521

cvss
6.8
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
1.3%
EPSS 1.3% chance of exploitation in 30 days, percentile 70%
public exploits
0
none known

Summary

A buffer overflow vulnerability in stm32_mw_usb_host of STMicroelectronics in versions before 3.5.1 allows an attacker to execute arbitrary code when the descriptor contains more endpoints than USBH_MAX_NUM_ENDPOINTS. The library is typically integrated when using a RTOS such as FreeRTOS on STM32 MCUs.

Patch / fix

  • STMicroelectronics STM32Cube STM32 USB Host Library 3.5.1
  • micropython Ubuntu Pro 20.04 LTS 1.12-1ubuntu0.1~esm1
  • micropython Ubuntu Pro 22.04 LTS 1.17+ds-1.1ubuntu2+esm1
  • micropython Ubuntu Pro 24.04 LTS 1.22.1+ds-1ubuntu0.24.04.1~esm1

ubuntu advisories UBUNTU-CVE-2021-42553

Ubuntu security data © Canonical Ltd., from https://github.com/canonical/ubuntu-security-notices via OSV; changed: normalised to fixed package versions per release. CC BY-SA 4.0

CISA SSVC

Exploitation
none
Automatable
no
Technical impact
total
Assessed
18 mo ago

Exploit prediction

1.30% chance of exploitation in the next 30 days, higher than 70% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by version score vector
CNA 3.1 6.8 CVSS:3.1/AV:P/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
NVD 3.1 9.8 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

Affected products

  • STMicroelectronics STM32Cube STM32 USB Host Library

Classification

Weakness
  • CWE-120 Buffer Copy without Checking Size of Input

References

Sources

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.